LED-BASED FIBER OPTIC OXYGEN SENSOR USING SOL-GEL COATING

An intrinsic evanescent wave fibre optic sensor for oxygen is reported, The sensor is based on the quenching of fluorescence from a ruthenium complex trapped m the cage-like structure of a sol-gel-derived porous film on a de-clad section of multimode optical fibre. The sensor exhibits excellent performance using blue LED excitation and silicon photodiode detection, and establishes the viability of low-cost portable sensor devices based on the sol-gel process. Gas phase measurement data over the range 0-100% oxygen exhibit high signal-to-noise ratio (approximately 150), good repeatability and short response time (< 5s).